X-Git-Url: http://git.openwrt.org/?a=blobdiff_plain;f=toolchain%2Fmusl%2Fpatches%2F500-0004-restore-lock-skipping-for-processes-that-return-to-s.patch;fp=toolchain%2Fmusl%2Fpatches%2F500-0004-restore-lock-skipping-for-processes-that-return-to-s.patch;h=0000000000000000000000000000000000000000;hb=aaec2ad13b18086e2aaf9ca9152827c50e578bc0;hp=83a6d0247a9f5a20ab8aefdae961f884f9e31a65;hpb=da5bb885e17cf77caea70adcf473f1fb95448553;p=openwrt%2Fstaging%2Fchunkeey.git

diff --git a/toolchain/musl/patches/500-0004-restore-lock-skipping-for-processes-that-return-to-s.patch b/toolchain/musl/patches/500-0004-restore-lock-skipping-for-processes-that-return-to-s.patch
deleted file mode 100644
index 83a6d0247a..0000000000
--- a/toolchain/musl/patches/500-0004-restore-lock-skipping-for-processes-that-return-to-s.patch
+++ /dev/null
@@ -1,90 +0,0 @@
-From 8d81ba8c0bc6fe31136cb15c9c82ef4c24965040 Mon Sep 17 00:00:00 2001
-From: Rich Felker <dalias@aerifal.cx>
-Date: Fri, 22 May 2020 17:45:47 -0400
-Subject: [PATCH 4/4] restore lock-skipping for processes that return to
- single-threaded state
-
-the design used here relies on the barrier provided by the first lock
-operation after the process returns to single-threaded state to
-synchronize with actions by the last thread that exited. by storing
-the intent to change modes in the same object used to detect whether
-locking is needed, it's possible to avoid an extra (possibly costly)
-memory load after the lock is taken.
----
- src/internal/libc.h         | 1 +
- src/malloc/malloc.c         | 5 ++++-
- src/thread/__lock.c         | 4 +++-
- src/thread/pthread_create.c | 8 ++++----
- 4 files changed, 12 insertions(+), 6 deletions(-)
-
---- a/src/internal/libc.h
-+++ b/src/internal/libc.h
-@@ -21,6 +21,7 @@ struct __libc {
- 	char can_do_threads;
- 	char threaded;
- 	char secure;
-+	volatile signed char need_locks;
- 	int threads_minus_1;
- 	size_t *auxv;
- 	struct tls_module *tls_head;
---- a/src/malloc/malloc.c
-+++ b/src/malloc/malloc.c
-@@ -26,8 +26,11 @@ int __malloc_replaced;
- 
- static inline void lock(volatile int *lk)
- {
--	if (libc.threaded)
-+	int need_locks = libc.need_locks;
-+	if (need_locks) {
- 		while(a_swap(lk, 1)) __wait(lk, lk+1, 1, 1);
-+		if (need_locks < 0) libc.need_locks = 0;
-+	}
- }
- 
- static inline void unlock(volatile int *lk)
---- a/src/thread/__lock.c
-+++ b/src/thread/__lock.c
-@@ -18,9 +18,11 @@
- 
- void __lock(volatile int *l)
- {
--	if (!libc.threaded) return;
-+	int need_locks = libc.need_locks;
-+	if (!need_locks) return;
- 	/* fast path: INT_MIN for the lock, +1 for the congestion */
- 	int current = a_cas(l, 0, INT_MIN + 1);
-+	if (need_locks < 0) libc.need_locks = 0;
- 	if (!current) return;
- 	/* A first spin loop, for medium congestion. */
- 	for (unsigned i = 0; i < 10; ++i) {
---- a/src/thread/pthread_create.c
-+++ b/src/thread/pthread_create.c
-@@ -118,8 +118,8 @@ _Noreturn void __pthread_exit(void *resu
- 	 * until the lock is released, which only happens after SYS_exit
- 	 * has been called, via the exit futex address pointing at the lock.
- 	 * This needs to happen after any possible calls to LOCK() that might
--	 * skip locking if libc.threads_minus_1 is zero. */
--	libc.threads_minus_1--;
-+	 * skip locking if process appears single-threaded. */
-+	if (!--libc.threads_minus_1) libc.need_locks = -1;
- 	self->next->prev = self->prev;
- 	self->prev->next = self->next;
- 	self->prev = self->next = self;
-@@ -339,7 +339,7 @@ int __pthread_create(pthread_t *restrict
- 		~(1UL<<((SIGCANCEL-1)%(8*sizeof(long))));
- 
- 	__tl_lock();
--	libc.threads_minus_1++;
-+	if (!libc.threads_minus_1++) libc.need_locks = 1;
- 	ret = __clone((c11 ? start_c11 : start), stack, flags, args, &new->tid, TP_ADJ(new), &__thread_list_lock);
- 
- 	/* All clone failures translate to EAGAIN. If explicit scheduling
-@@ -363,7 +363,7 @@ int __pthread_create(pthread_t *restrict
- 		new->next->prev = new;
- 		new->prev->next = new;
- 	} else {
--		libc.threads_minus_1--;
-+		if (!--libc.threads_minus_1) libc.need_locks = 0;
- 	}
- 	__tl_unlock();
- 	__restore_sigs(&set);